Fuel Cell Stack Frame with Venting Holes
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Solution Overview
Problem
In fuel cell stacks with a double sealing structure, the confined air can cause adhesive breakage and uneven surface pressure when a load is applied during stacking, as the air trapped between the inner and outer sealing parts pushes out and breaks the adhesive before it cures.
Innovation Solution
The cell structure incorporates communication holes in the frames and separators that allow air to escape between the sealing parts, preventing pressure buildup and adhesive breakage by releasing air to the outside, even after the adhesive has cured.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a double sealing structure is adopted in the periphery of fuel cell stacks, then sealing reliability is improved, but air pressure buildup causes adhesive breakage and manufacturing defects
Solution Approach 1:
The frame is segmented by forming communication holes that divide the sealed space into multiple regions, allowing air to escape from the closed space between inner and outer sealing parts. This segmentation prevents air pressure buildup while maintaining the double sealing structure's reliability
Solution Approach 2:
The communication holes act as intermediary channels that mediate between the sealed internal space and the external environment. These holes allow air to pass through the frame from the closed space to the outside, preventing adhesive breakage while preserving the sealing function
2Volume of moving object
If thin film frames are used to decrease unit cell thickness, then device compactness is improved, but the frame structure becomes more susceptible to deformation under load
Solution Approach 1:
The patent utilizes thin film frames that are flexible yet sufficient for the application. The communication holes are formed in these thin films, demonstrating that the thin film structure can accommodate additional features without compromising its fundamental thickness advantage
Solution Approach 2:
By segmenting the frame with communication holes, the structural integrity is maintained while allowing pressure equalization. The segmentation prevents deformation propagation and reduces stress concentration points in the thin film structure
3Reliability
If adhesive is applied in a line shape for sealing, then sealing continuity is improved, but air pressure pushes out and breaks the adhesive before curing
Solution Approach 1:
The communication holes are formed in advance in the frame structure, creating preliminary escape paths for air before adhesive bonding occurs. This preliminary anti-action prevents air pressure buildup that would otherwise push out and break the adhesive lines during the curing process
Solution Approach 2:
The harmful air pressure is extracted from the sealed space through the communication holes. By removing the air pressure source that causes adhesive breakage, the adhesive can cure properly and maintain its bonding strength
Data Source
AI summary
A cell structure for a fuel cell stack that is formed by stacking unit cells C each including a membrane electrode assembly 1 and a pair of separators 2 holding the membrane electrode assembly 1 therebetween. The membrane electrode assembly 1 includes a frame 3 in the periphery having such a size as to extend outward over the edges of the separators 2. Communication holes 21, 22 in communication with the front and back sides are formed in the frame 3 in an area from a sealing part 11 between frames 3 adjacent in the cell stacking direction to a sealing parts 12 between the membrane electrode assembly 1 and the separators 2. The air in a space Q formed between the inner and outer sealing parts 11, 12 is allowed to be released to the outside through the communication holes 21, 22, and a breakage of the adhesive of the sealing parts 11, 12 is thereby prevented.